Download UltimaDark - The Fastest Dark Mode Extension for Firefox. UltimaDark uses agressive & smart techniques to turn even the sunniest websites into realms of darkness.
Although it works well, this is so experimental, it makes lab rats look like seasoned professionals.
Go ahead, embrace the ...
The issue is more that the extension doesn't seem to properly let sites bypass or something. I have to turn the extension off and refresh to get picture back.